The task of managing and uploading the localised assets of your iOS app
in a tedious one. When the number of supported languages increases, the
effort needed via the web interface at https://itunesconnect.apple.com
is increased accordingly. Apple’s iTMSTransporter tool gives you the
ability to download and upload App Store Packages (.itmsp) from the
command line. However, altering the data requires an XML file
manipulation.

An easier way is to use itunes_transporter_generator (itmsp) ,
which lets you add your metadata in a YAML app configuration.
Running itmsp converts the YAML file to an .itmsp package that can
be uploaded using iTMSTransporter. However, when multiple localized
assets are involved, this solution leads to editing a huge unmanageable
YAML file.

This tool, itunes_file_system (itunesfs) requires that you
organise your assets (screenshots, description, keywords etc)in a
specific file hierarchy. Running itunesfs produces an intermediate
YAML configuration file and, if you have itmsp installed, it uses it
to generate the final .itmsp package. You can then uploaded it on iTunes
Connect using iTMSTransporter.